On website Support Apple we can read that, iOS version 6.1.2 improves error handling Exchange calendar, which could lead to increased activity in the network (synchronization), and reduced battery life.

This description is very superficial and does not mention that the “increased network activity” caused a rapid increase Exchange Transaction Logs that could cause dismount databases with mailboxes.

However it’s good that Apple finally noted that this problem occurred.

Update to iOS 6.1.2 weight 12MB and was released on 02/19/2013

If you seen increased loads on Exchange Servers (growing log files) you should encourage all iOS users to update to iOS 6.1.2.

Yes, when you get list of all deviceOS you can do with them what you want, also you can add:
… unlimited | where { $_.DeviceOS -like “*iOS*”} | Sort-Object -Property DeviceOS | ft identity, deviceos -auto
then you will get only devices with iOS any version.